Highly efficient electrically conductive networks in carbon‐black‐filled ternary blends through the formation of thermodynamically induced self‐assembled hierarchical structures

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ABSTRACTHighly efficient electrical conductive networks were constructed in carbon‐black (CB)‐filled polyoxymethylene (POM)–thermoplastic polyurethane (TPU)–polyamide 6 (PA6) ternary blends through the formation of a hierarchical structure composed of a minor PA6 phase as droplets inside one major phase (TPU) and CB particles localized at the TPU–PA6 interface by thermodynamically induced self‐assembly. The hierarchical structure was thermodynamically predicted on the basis of the minimization of total interfacial energies and confirmed by electron microscopy. The degrees of the TPU phase continuity before and after the addition of PA6 were determined by solvent‐extraction experiments. The percolation threshold of CB decreased by 50% compared to that in the POM–TPU binary blend because of the more efficient formation of a CB conductive network through CB‐covered PA6 domains inside the TPU phase. The hierarchical structure not only increased the electrical conductivity of the composites but also improved their thermal stability in comparison with the simple structure formed by the homogeneously dispersed CB particles in POM. The method reported in this article can offer possibilities for improving the comprehensive properties of the conductive composites and the widening of their applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45877.